Cylindrical marine boiler with superheater



D 17, 1929- s. HOFFMANN CYLINDRIGAL mam 1 0mm wm: SUPERHEATER Filed July 31, 1928 Patented Dec. 17, 1929 UNITED STATES PATENT OFFICE.

SIMON HOFFM ANN, OF KASSEIrWILHELMSHOTIE, GERMANY, ASSIGNOB TO SOHMIDTSCZHE HEISSDAMPF-GESELLSCHAFT MIT IBESCHRANKTEB HAITUNG, OF KASSEL-WILHELMSHOHE, GERMANY, A CORPORATION OF GERMANY GYLINDBIGAL MARINE BOILER WITH SUPERHEATER I Application filed July 31, 1928, Serial No. 296,616, and in Germany September 8, 1927.

My invention relates to improvements in cylindrical marine boilers with superheaters and'one or more flame tubes or flues between the tubes which constitute or comprise the furnace chambers and form the first gas path and the smoke tubes which lead to the chimney and form a third gas path of the boiler. The said tubes or flues between the furnace chamber and the smoke tubes form an intermediate or second hot gas passage. The hot gases, therefore, flow through the boiler along three paths and in so doing make a twice repeated bend.

The object of my invention is an improved boiler of this kind with two working pressures and superheaters for the high-pressure and the low-pressure part of the boiler. According to my invention, the superheater for the high-pressure part isarranged in the flue forming the second path of the hot gases and the superheater for the low-pressure part is arranged in the second return chamber joining the intermediate flame tube or flue to the smoke tubes formin the third gas passage.

The advantage 0 the arrangement in accordance with my invention lies chiefly in the fact that higher superheats are obtained, i. e. higher steam superheats, than is possible in the usual type of smoke tube superheater so while the escaping gases are not cooled to such an extent that the boiler efliciency sufiers. The hot gases are already cooled to such an extent in the first gas passage and in the first return chamber that there is no fear of the as burning of the superheater elements-in the intermediate flame tube or flue while, on the other hand, the temperature of the hot gases is still sufliciently high to enable the desired degree of superheaterto be obtained, F ur- 40 ther the efiicient utilization of heat in the gases is independent of the degree of superheat because, after the gases have passed beond the superheaters, there is a boiler heatmg surface which is approin'mately as large as in the standard arrangement of smoke tubes in cylindrical marine boilers,

One embodiment of the invention is illustrated in the accompanying drawing in which Fig. 1 is a longitudinal section of a twopressure cylindrical marine boiler equipped with steam superheating apparatus according to my invention and Fig. 2 is a transverse section on the line 1-1 of Figure 1.

The boiler as shown in the drawing has a low-pressure part formed by an usual smoketube boiler 12, whilst the high pressure part is formed as an indirectly heated boiler. The generation of the high-pressure steam takes place in a steam-water drum 1 through a heat carrier- (for instance, water and steam obtained therefrom), which passes its heat on the working boiler'water in drum 1 through heating elements 2, which form part of a closed ipe system also comprising tubes 3 situate in the furnace chamber a of the boiler. The tubes 3, as shown, are also so disposed as to form a protection against heat for the wall of the first return chamber 6.

These tubes 3 extend between the lower collecting chamber 4 and the upper distributing chambers 5. The latter are joined to the upper ends of the heating elements 2 through the uptake pipes 6, and the lower ends of the said'heating elements 2 are joined to the collecting chamber or chambers 4 through downtake pipes 7. In two middle flame or smoke tubes d, d which act as a flue extending between the first return chamber 6 from the furnace chamber a to the second return chamber f, are arranged the pipes g of the high pressure superheater. The steam from the highpressure boiler 1 is conducted to this su erheater 9 through a transmissionpipe 8 and the superheated steam is delivered from the superheater through .the pipe t. The superheater g for the low pressure boiler b is situated in the second return chamber f. between the middle flame tubes d, d and the tubes 6 leading intothe smoke box 0. The steam from the low pressureboiler b is led to 90 thesuperheater 9 through a transmission pipe 8 the superheated low pressure steam passing out from the superheater through the pipe Havin now particularly described and as- 95 certaine the nature of my said invention and in what manner the same is to be performed,

I declare that what- I claim is;

A cylindrical marine boiler with two working pressures and superheaters for the highpressure and the low-pressure part having a furnace chamber forming a first hot gas passage, a flue within the boiler forming a second gas passage, smoke tubes forming a third gas passage, a first return chamber between the first and the second gas passage, a second return chamber between the second and the third gas passage, a superheater for the high-pressure part of the boiler arranged in said second gas passage and a superheater for the low-pressure part of the boiler arranged in said second return chamber.

In testimony whereof I affix my signature.

' SIMON HOFFMAN N. 

